Forbidden Passage

 is a quest in Tyranny.

Synopsis
Raetommon has gone deep into the Twin Rivers Oldwalls with Zdenya as his captive. Track him down and retrieve the Forge-Bound master.

Walkthrough

 * Deal with Flatfoot Ferris at the entrance. Kill him or use Subterfuge 57 to acquire the Amith Torchkey.
 * Make your way through Twin Rivers Oldwalls - Brotherhood Camp by activating the beacon with the Amith and extending the bridges. Head northwest to Twin Rivers Oldwalls - Depths.
 * Make your way towards the north-western corner of the location, picking up the Rho Torchkey on the way. Use it to power up the beacon. In the beacon room, use the Citren on the upper left beacon, Rho on the central, and Amith on the upper right beacon to activate the floorplate.
 * Use it to open the door to the side. Continue to Lethian's Crossing Oldwalls - Antechamber.
 * Approach the central platform to confront Raetommon. After wading through his gloating, indicating that he's gone completely bonkers, you can attack or intimidate him (Athletics 52) to hand over the torchkey. The latter option causes him to attack, but he does so without the support of the Bane or the Havoc.
 * Use the torchkeys on the beacons to return outside. The Emir (green) goes to the lower left beacon, Citren (yellow) to lower right, Rho (red) to upper left, Amith (violet) to the upper right.
 * Crap. After three torchkeys are activate, the Havoc wakes up and attack. Kill it. Pick up the Greater Healing Potion recipe from its remains.
 * Head upstairs. You can free or kill Zdenya. The latter is a Betray Alliance moment.
 * Assuming you've freed her, direct her to Graven Ashe.
 * Return to Eldian and either return the Magebane or give it to the Crossing (its presence at the Crossing determines the ending). Note that a Disfavored garrison is now stationed at the Crossing (if they were not already there).
 * Return to Graven Ashe.